MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, China.
Front Cell Infect Microbiol. 2021 Apr 1;11:652432. doi: 10.3389/fcimb.2021.652432. eCollection 2021.
In , type III secretion system 1 (T3SS1) is a major virulence factor that delivers effectors into the host eukaryotic cytoplasm; however, studies on its infection mechanism are currently limited. To determine the function of the gene, we constructed the deletion mutant Δ and complementation strain CΔ. Compared with those of wild-type POR-1 and CΔ, the cytotoxic, adherent, and apoptotic abilities of Δ in HeLa cells were significantly reduced ( < 0.01). Furthermore, in infected HeLa cells, the mutant strain reduced the translocation rates of VP1683 and VP1686 effectors compared to the wild-type and complementation strains. A BLAST search showed that is homologous to the MixH needle protein of , indicating that the gene encodes the needle protein of T3SS1 in . Additional translocation assays showed that VPA0226 translocated into the HeLa eukaryotic cytoplasm T3SS1, secretion assays showed that VPA0226 can be secreted to supernatant by T3SS1, indicating that VPA0226 belongs to the unpublished class of T3SS1 effectors. In conclusion, our data indicate an essential role of vscF in T3SS1 and revealed that VPA0226 can be secreted into the host cell cytoplasm T3SS1. This study provides insights into a previously unexplored aspect of T3SS1, which is expected to contribute to the understanding of its infection mechanism.
在 POR-1 中，III 型分泌系统 1（T3SS1）是一种将效应器输送到宿主真核细胞质中的主要毒力因子；然而，目前对其感染机制的研究还很有限。为了确定 基因的功能，我们构建了 缺失突变体 Δ和互补菌株 CΔ。与野生型 POR-1 和 CΔ相比，Δ在 HeLa 细胞中的细胞毒性、黏附和凋亡能力显著降低（<0.01）。此外，在感染的 HeLa 细胞中，与野生型和互补菌株相比，突变株降低了 VP1683 和 VP1686 效应器的易位率。BLAST 搜索表明 与 的 MixH 针蛋白同源，表明 基因编码 POR-1 中 T3SS1 的针蛋白。额外的易位试验表明，VPA0226 可通过 T3SS1 易位到 HeLa 真核细胞质中，分泌试验表明 VPA0226 可通过 T3SS1 分泌到上清液中，表明 VPA0226 属于 T3SS1 效应器的未公布类别。总之，我们的数据表明 vscF 在 POR-1 T3SS1 中具有重要作用，并揭示了 VPA0226 可以通过 T3SS1 分泌到宿主细胞细胞质中。这项研究提供了对 T3SS1 一个以前未被探索的方面的深入了解，有望有助于理解其感染机制。
